AD 99-08-04

This amendment adopts a new airworthiness directive (AD), applicable to certain Bombardier Model DHC-8-100, -200, and -300 series airplanes, that requires modification of the flight compartment door; repetitive inspections for wear of the flight compartment door hinges following modification; and repair or replacement of the hinges with new hinges, if necessary. This amendment is prompted by a report that the door lock mechanism of the flight compartment door jammed and could not be opened using the alternate release mechanism. The actions specified by this AD are intended to prevent failure of the alternate release mechanism of the flight compartment door, which could delay or impede the evacuation of the flightcrew during an emergency. Such failure also could result in the flightcrew not being able to assist passengers in the event of an emergency.

Final Rule

99-08-04 BOMBARDIER, INC. (Formerly de Havilland, Inc.): Amendment 39-11109. Docket 97-NM-04-AD.

Applicability: Model DHC-8-100, -200, and -300 series airplanes having serial numbers 3 and subsequent; certificated in any category.

NOTE 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (c) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To prevent failure of the alternate release mechanism of the flight compartment door, which could delay or impede the evacuation of the flightcrew and passengers during an emergency, accomplish the following:

(a) Within 90 days after the effective date of this AD, modify the lower hinge assembly and main door latch (Modification 8/2337) of the flight compartment door, in accordance with Bombardier Service Bulletin S.B. 8-52-39, Revision `D,' dated February 27, 1998.

NOTE 2: Modification of the flight compartment door accomplished prior to the effective date of this AD in accordance with Bombardier Service Bulletin S.B. 8-52-39, dated August 30, 1996; Revision `A,' dated October 31, 1996; Revision `B,' dated July 4, 1997; or Revision `C,' dated September 1, 1997; is considered acceptable for compliance with the modification required by paragraph (a) of this AD.

(b) Within 800 flight hours after accomplishment of the modification required by paragraph (a) of this AD, inspect the hinge areas around the hinge pin holes of the flight compartment door for wear, in accordance with Bombardier Service Bulletin S.B. 8-52-39, Revision `C,' dated September 1, 1997, or Revision `D,' dated February 27, 1998.

(1) If no wear is detected, or if the wear is less than or equal to 0.020 inch in depth, repeat the inspection thereafter at intervals not to exceed 800 flight hours.

(2) If any wear is detected and its dimension around the hinge pin holes is less than 0.050 inch and greater than 0.020 inch in depth, prior to further flight, perform the applicable corrective actions specified in the service bulletin. Repeat the inspection thereafter at intervals not to exceed 800 flight hours.

(3) If any wear is detected and its dimension around the hinge pin holes is greater than or equal to 0.050 inch in depth, prior to further flight, replace the worn hinges with new hinges in accordance with the service bulletin. Repeat the inspection thereafter at intervals not to exceed 800 flight hours.

Alternative Methods of Compliance

(c) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, New York Aircraft Certification Office (ACO), FAA, Engine and Propeller Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, New York ACO.

NOTE 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the New York ACO.

Special Flight Permits

(d) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

Incorporation by Reference(e) The actions shall be done in accordance with Bombardier Service Bulletin S.B. 8-52-39, Revision `C,' dated September 1, 1997, and Bombardier Service Bulletin S.B. 8- 52-39, Revision `D,' dated February 27, 1998; as applicable. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Bombardier, Inc., Bombardier Regional Aircraft Division, Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW, Renton, Washington; or at the FAA, Engine and Propeller Directorate, New York Aircraft Certification Office, 10 Fifth Street, Third Floor, Valley Stream, New York; or at the Office of the Federal Register, 800 North Capitol Street, NW, suite 700, Washington, DC.

NOTE 4: The subject of this AD is addressed in Canadian airworthiness directive CF- 96-20R2, dated July 16, 1997.

(f) Thisamendment becomes effective on May 12, 1999.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain Bombardier Model DHC-8-100, -200, and -300 series airplanes was published as a supplemental notice of proposed rulemaking (NPRM) in the Federal Register on August 5, 1998 (63 FR 41741). That action proposed to require modification of the flight compartment door; repetitive inspections for wear of the flight compartment door hinges following modification; and repair or replacement of the hinges with new hinges, if necessary.

Comments Received

Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received.

Support for Proposed Rule

One commenter supports the proposed rule.

Request to Revise Applicability Statement

One commenter requests that the applicability statement of the proposed AD be revised to reflect the effectivity listing specified in Bombardier Service Bulletin S.B. 8-52-39, Revision D, dated February 27, 1998 (i.e., Model DHC-8 series airplanes having serial numbers 003 through 433 inclusive, except serial numbers 269, 408, and 413). The commenter points out that paragraph (a) of the proposed AD requires accomplishment of the modification specified in the subject service bulletin.

The FAA does not concur with the commenter s request. The applicability statement of the original NPRM [which was published in the Federal Register on July 11, 1997 (62 FR 37170)] read, "Model DHC-8-100, -200, and -300 series airplanes having serial numbers 3 through 433 inclusive, excluding serial numbers 269, 408, and 418; certificated in any category." The FAA revised the applicability of the supplemental NPRM in consonance with the Canadian airworthiness directive CF-96-20R2, dated July 16, 1997. This revision was made because the supplemental NPRM was revised to addrepetitive inspections for wear of the flight compartment door hinges following accomplishment of the required modification. These new repetitive inspections must be accomplished on all affected airplanes having serial numbers 3 and subsequent, regardless of whether the airplane has been modified.

Explanation of Changes Made to Supplemental NPRM

The FAA has revised the final rule to reflect the corporate name change of de Havilland, Inc. to Bombardier, Inc.

Conclusion

After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes described previously. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.

Interim Action

This is considered to be interim action. The manufacturer has advised the FAA that it currently is developing a modification that will eliminate the need for the repetitive inspections for wear of the flight compartment door hinges. Once this modification is developed, approved, and available, the FAA may consider additional rulemaking.

Cost Impact

The FAA estimates that 133 Bombardier Model DHC-8-100, -200, and -300 series airplanes of U.S. registry will be affected by this AD.

It will take approximately 4 work hours per airplane to accomplish the required modification, at an average labor rate of $60 per work hour. Required parts will be provided by the manufacturer at no cost to operators. Based on these figures, the cost impact of the modification required by this AD on U.S. operators is estimated to be $31,920, or $240 per airplane.

It will take approximately 2 work hours per airplane to accomplish the required inspection, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the inspection required by this AD on U.S. operators is estimated to be $15,960, or $120 perairplane, per inspection cycle.

The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted.

Regulatory Impact

The regulations adopted herein will not have substantial direct effects on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES."

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39 - AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

39.13 [Amended]

2. Section 39.13 is amended by adding the following new airworthiness directive: